So it does sound like a number of projects were keeping a list of wallets and were “re-airdropping” NFTs back to the corresponding wallet upon devnet wipes. This isn’t really advised as this isn’t the first time Sui has changed the way they derive addresses, but to each their own.
For the projects that were keeping a list of addresses, it is possible to link the old addresses to the new addresses with a bit of work. You can read more about it here: